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sound: enable interrupt after dma buffer initialization
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In snd_hdac_bus_init_chip(), we enable interrupt before
snd_hdac_bus_init_cmd_io() initializing dma buffers. If irq has
been acquired and irq handler uses the dma buffer, kernel may crash
when interrupt comes in.

Fix the problem by postponing enabling irq after dma buffer
initialization. And warn once on null dma buffer pointer during the
initialization.

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Yu Zhao authored and Mark Brown committed Sep 12, 2018
1 parent 542cede commit b61749a
Showing 1 changed file with 6 additions and 2 deletions.
8 changes: 6 additions & 2 deletions sound/hda/hdac_controller.c
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,8 @@ static void azx_clear_corbrp(struct hdac_bus *bus)
*/
void snd_hdac_bus_init_cmd_io(struct hdac_bus *bus)
{
WARN_ON_ONCE(!bus->rb.area);

spin_lock_irq(&bus->reg_lock);
/* CORB set up */
bus->corb.addr = bus->rb.addr;
Expand Down Expand Up @@ -479,13 +481,15 @@ bool snd_hdac_bus_init_chip(struct hdac_bus *bus, bool full_reset)
/* reset controller */
azx_reset(bus, full_reset);

/* initialize interrupts */
/* clear interrupts */
azx_int_clear(bus);
azx_int_enable(bus);

/* initialize the codec command I/O */
snd_hdac_bus_init_cmd_io(bus);

/* enable interrupts after CORB/RIRB buffers are initialized above */
azx_int_enable(bus);

/* program the position buffer */
if (bus->use_posbuf && bus->posbuf.addr) {
snd_hdac_chip_writel(bus, DPLBASE, (u32)bus->posbuf.addr);
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